A variety of self-assembled polymer micelles using block copolymers has been extensively explored as effective drug delivery carriers for anti-cancer drugs (Alakhov et al. (1999) Coll. Surfaces B: Biointerfaces, 16:113-134; Bronich et al. (1999) Coll. Surfaces B: Biointerfaces, 16:243-251; Allen et al. (1999) Coll. Surfaces B: Biointerfaces, 16:3-27; Nakanishi et al. (2001) J. Control Release, 74:295-302; Lavasanifar et al. (2002) Adv. Drug Deliv. Rev., 54:169-190; Carlsen et al. (2009) Curr. Opin. Coll. Interface Sci., 14:329-339; Kabanov et al. (2009) Angew Chem. Int. Ed. Engl., 48:5418-5429). Nanoscale polymer micelles have predominant features such as long blood circulation time, avoidance of renal excretion and passive targeting via enhanced permeability and retention effect (EPR effect) (Maeda, H. (2001) Adv. Enzyme Regul., 41:189-207). However, many nanoscale polymer micelles lack stability and can leak the bioactive agent quickly when administered to a subject. To avoid the negative side effects associated with the premature release of the bioactive agent, micelles of greater stability are desired. Additionally, micelles capable of delivering more than one compound (e.g., a hydrophobic and a charged compound) at the same time are also desired to deliver synergistic effects.